1. Field of the Invention
The invention relates to a utility pole and, more particularly, to a grounding plate for a utility pole.
2. Brief Description of Prior Developments
Equipment and system grounding plays a critical role in an utility's electrical system reliability. Commonly, ground plates are attached at the base of a pole before it is lowered into the ground. Solid wire connections are made to these ground plates and run up the pole to the top; to act as supplemental grounding.
According to the U.S. National Electrical Code, article 250.52(A) (6), for Plate Electrodes: Each plate electrode shall expose not less than 0.186 m2 (2 ft2) of surface to exterior soil. Electrodes of iron or steel plate shall be at least 6.4 mm (1.4 in.) in thickness. Electrodes of non-ferrous metal shall be at least 1.5 mm (0.06 in.) in thickness.
Several current styles of pole ground plates available in the market supply a 8 inch by 39 inch flat copper plate that is wrapped around the base of the pole and nailed or screwed to the pole. The exposed area to the ground qualifies as ground surface area, thus, dictating somewhat the length/width of the plate. The copper plating on the inside portion (adjacent to the wooden pole) does not count as qualified surface area.
Various different devices for grounding, used with poles inserted into the ground, are know. Besides the wrap-around plate noted above, U.S. Pat. No. 6,815,607 discloses a base support attached to the bottom of the pole. Other bottom attached plates include those described in U.S. Pat. Nos. 5,909,005, 2,545,048 and 2,455,641 for example.
There is a desire to decrease the amount of material that is used for a pole grounding plate, thereby reducing material costs, while still meeting the National Electrical Code standard for plate electrodes.